[arm-allstar] Adding a real-time clock (i2c etc)---script update

[Larry Aycock]

Hello All,

I tried to find the original message below to respond to, but I think it was permanently deleted.  David updated the script below for HamVOIP to install an RTC.  I ran this script and have some questions.


  1.  After running the script, how can I tell if the RTC is working correctly?
  2.  Do I need to add anything to other files to get the system to use the RTC when rebooting the Pi?
     *   I've seen other guides online mention adding some lines to the RC.LOCAL file to find and read from the RTC on boot.  Do I need to do something like this?
     *   The last two lines in the script below enables and starts the RTC.  Do I need to do that each time the node reboots?

I'm still learning the Linux system and how it all works.  I'm just not sure if the script below sets everything for me so that when the node reboots, it uses the RTC, or if there are additional steps I need to do to make that happen.  More clarification would be greatly appreciated.

73,
Larry
N6LKA



Below is the post from David with the script.

Here is that setup script sortof customized to HamVoIP. It runs okay on my
dev RPi4B....

73, David KB4FXC

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#!/bin/bash

cp /boot/config.txt /tmp/config.tmp
echo 'device_tree_param=i2c_arm=on' >> /tmp/config.tmp

j=$(grep 'device_tree_param=i2c_arm=on' /tmp/config.tmp | wc | awk '{print $1}')

if [ "$j" == "1" ] ; then
        cp /tmp/config.tmp /boot/config.txt
else
        echo -e "\n\ndevice_tree_param NOT SET CORRECTLY!\n"
        echo "Check your /boot/config file and manually correct:"
        echo -e "\n\tdevice_tree_param=i2c_arm=on"
        echo -e "\n\nThen, run this script again....\n\n"
        exit 1
fi

pacman -S --needed --noconfirm i2c-tools

modules_file="/etc/modules-load.d/raspberrypi.conf"
cp "$modules_file" /tmp/rtc.tmp
echo rtc-ds1307 >> /tmp/rtc.tmp
echo i2c-dev >> /tmp/rtc.tmp
sort /tmp/rtc.tmp | uniq > "$modules_file"

mkdir -p /usr/lib/systemd/scripts/
cat > /usr/lib/systemd/scripts/rtc << END
#!/bin/bash
# create an i2c device DS1307 (works also for DS3231)
# set systemclock from external i2c-rtc
echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
hwclock -s
END

chmod 755 /usr/lib/systemd/scripts/rtc

cat > /etc/systemd/system/rtc.service << END
[Unit]
Description=RTClock
Before=network.target

[Service]
ExecStart=/usr/lib/systemd/scripts/rtc
Type=oneshot
[Install]
WantedBy=multi-user.target
END

systemctl enable rtc
systemctl start rtc

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